This section is intended to introduce the reader to various aspects of art, which may be related to various embodiments of the present invention that are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Computer systems generally include hardware resources, including but not limited to one or more central processing units, such as microprocessors, and one or more memory devices, such as random access memory (RAM) devices, which make up the system memory. An operating system provides the software that manages the hardware and software resources of the computer system, including the microprocessor and system memory. The operating system generally provides a user interface such that the resources may be accessed and controlled by a user.
When a computer is initially powered on, the system memory is empty. To configure the computer system to facilitate the use of its resources, the operating system is loaded into the system memory. The process of launching the operating system is generally referred to as the “system boot.” Once the boot process is complete and the operating system is loaded into the system memory, the operating system may be implemented to control and manage both hardware and software resources. However, before the system boot, the system memory cannot be implemented to execute commands because the operating system has not been loaded into system memory. To provide boot instructions for loading the operating system, a basic input/output system (BIOS) is generally provided. The system BIOS is typically stored in a read only memory (ROM) chip or a flash memory chip in the computer system. The BIOS provides instructions necessary to load the operating system and to implement other initialization and testing functions during the system boot.
Because each computer system may include different hardware components, the BIOS software is also configured to perform a power-on self-test (POST) to test the functionality of the different hardware components on the computer system. The POST generally refers to a diagnostic testing sequence executed by the BIOS software to determine whether the random access memory (RAM), peripheral devices, such as disk drives, and any other hardware components are operating properly. Further, a number of devices may be coupled to the computer system through expansion slots. Devices such as expansion memory, network devices, video and audio chips, etc., may be included on expansion cards which are configured to be coupled to the computer system through the expansion slots. Each of the expansion cards may include an expansion ROM that includes BIOS software for devices on the expansion card. At system boot, the system BIOS configures the computer system in accordance with the current resources, including any expansion cards that may be coupled into the computer system. Accordingly, the system BIOS also facilitates the activation of the additional BIOS that may be included on the expansion cards.
As can be appreciated, the more complex the system configuration and the more resources included in the system, the longer the booting of the computer system may take. In many instances, booting the computer system may take several minutes. In certain applications, this timing penalty may be disadvantageous.
Once the boot process is complete and the operating system is up and running, expansion boards or cards may be added or removed from the computer system. “Hot swapping” or “hot plugging” generally refers to replacing components in a computer system while the system is powered on. If an expansion board is replaced after the system boot sequence, the computer system is generally rebooted such that it can be reconfigured to include the components on the replacement expansion card. As can be appreciated, initiating a power cycle to reboot the system generally incurs the time penalty, since the system is being completely rebooted, thereby mitigating some of the advantages of hot-swapping.